The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Compression ignition engines, such as diesel engines, may produce particulate matter (PM) that is filtered from exhaust gas by a PM filter. The PM filter reduces emissions of PM generated during combustion. Over time, the PM filter becomes full and may restrict the flow of exhaust gas through the PM filter. PM that has collected within the PM filter may be removed by a process called regeneration. During regeneration, PM within the PM filter may be combusted.
Regeneration may be accomplished, for example, by increasing a temperature of the exhaust gas entering the PM filter. A hydrocarbon (HC) dosing unit may inject fuel into an exhaust system upstream from one or more exhaust components, such as an oxidation catalyst, and the PM filter. Most of the injected fuel mixes with the exhaust gas and combusts in the oxidation catalyst. The combustion heats the exhaust gas, thereby increasing the temperature of the exhaust gas entering the PM filter. A flow rate of the injected fuel controls the temperature of the exhaust gas to a regeneration temperature. The increased temperature of the exhaust gas may cause the PM to combust.